1. Field Of The Invention
This invention relates to banded radial run-flat pneumatic tires and, more particularly, to banded tires having a transversely segmented band.
2. Background Of The Invention
The run-flat pneumatic tire is an area of tire technology that has engaged investigators over the years. A run-flat tire is one designed to be able to support a vehicle for operation at reasonable speeds for some predetermined distance even if the tire has partially or totally lost its inflation pressure. A recent successful development in the art of run-flat tires is the band-reinforced radial tire invented by one of the inventors in the present invention, Edward G. Markow, which banded tire is the subject of U.S. Pat. No. 4,111,249, assigned to the assignee of the present invention. The tire of the present invention is in the class of banded tires set forth in the aforementioned patent to Edward G. Markow, which is incorporated herein by reference.
A factor in the design of banded run-flat tires that affects the handling of the vehicle on which the tires are mounted is the bending stiffness of the band across the tire with respect to the bending stiffness circumferentially. Performance of a banded run-flat tire can be improved in a significant manner if the band is constructed such that its bending stiffness in a lateral direction across the band is substantially less than the bending stiffness circumferentially.
2. Description Of The Prior Art
The present invention relates to a banded radial run-flat pneumatic tire having a transversely segmented band. In the prior art, banded radial run-flat tires are disclosed in the Markow patent, U.S. Pat. No. 4,111,249, referenced previously herein. Unlike the transversely segmented bands of the present invention, that Markow patent teaches a solid unsegmented band having a width substantially spanning the width of the crown of the tire.
In the prior art, also, Arthur H. Marks, in U.S. Pat. No. 840,503, teaches a run-flat tire having one or more flat, comparatively heavy metal rings, preferably of steel, embedded in the tire crown. In Marks, however, the object is to produce a tire that has a practically rigid tread such that there is little or no flattening of the tire at the point of contact with the ground. A rigid tire thus is not a run-flat tire of a class in which a comparatively thin band is employed in the crown of the tire, the resilient thin band being supported and stabilized by a multiplicity of radial spoke-like elements in the sidewalls of the tire. Further, there is nothing disclosed in Marks that teaches a segmented band having a bending stiffness circumferentially that is considerably greater than the bending stiffness laterally across the tire. Because of the mentioned considerations, the tire of Marks would be totally unacceptable for present day use because of ride, handling, and service life deficiences inherent in a tire provided with a heavy, rigid metal band in its crown.